Colloidal dispersions

ABSTRACT

The tendency of a liquid hydrocarbon fuel to produce smoke when it is burned is reduced by incorporating into the fuel a colloidal dispersion of a sulphate, phosphate, or halide of an alkaline earth metal, the average size of the colloidally dispersed salt being less than 0.2 micron. The invention is particularly applicable to fuels for diesel engines. To prepare the dispersion, an alkaline earth metal oxide, hydroxide, carbonate, phenate, or salt of any weak acid is first dispersed in a lubricating oil or hydrocarbon fuel with the aid of a dispersing agent such as a phosphosulfurized hydrocarbon, an alkyl phenol or bisphenol, or a long-chain fatty acid amine. The dispersion is then treated with a hydrogen halide, or hydrochloric, sulphuric or phosphoric acid, or with an ammonium or volatile amine salt of one of those acids, thereby forming the desired dispersed salt in situ. The product is usually a concentrate which is then added to hydrocarbon fuel in the desired quantity.

United States Patent Burnop 1 Feb. 22, 1972 [54] COLLOIDAL DISPERSIONS 3,348,932 10/1967 Kukin ..44/57 X 3,410,671 11/1968 LeSuer.... ...44/51 [72] Inventor: Victor C. E. Burnop, Church Croft, West Challow near wamage, England 3,437,465 4/1969 LeSuer ..44/51 [22] Filed: Aug. 3, 1970 Primary Examiner-Daniel E. Wyman Assistant Examiner-W. J. Shine [21] W Nod 64,148 Att0meyPearlman&Stahl Related US. Application Data [57] ABSTRACT [63] continuation of 660396 1967 The tendency of aliquid hydrocarbon fuel to produce smoke abandoned.

when it is burned is reduced by incorporating into the fuel a colloidal dispersion of a sulphate, phosphate, or halide of an alkaline earth metal, the average size of the colloidally dispersed salt being less than 0.2 micron. The invention is particularly applicable to fuels for diesel engines. To prepare the dispersion, an alkaline earth metal oxide, hydroxide, carbonate, phenate, or salt of any weak acid is first dispersed in a lubricating oil or hydrocarbon fuel with the aid of a dispersing agent such as a phosphosulfurized hydrocarbon, an alkyl phenol or bisphenol, or a long-chain fatty acid amine. The dispersion is then treated with a hydrogen halide, or hydrochloric, sulphuric or phosphoric acid, or with an ammonium or volatile arnine salt of one of those acids, thereby forming the desired dispersed salt in situ. The product is usually a concentrate which is then added to hydrocarbon fuel in the desired quantity.

7 Claims, No Drawings COLLOIDAL DISPERSIONS This application is a continuation of application Ser. No. 660,896, filed Aug. 16, 1967, now abandoned.

This invention relates to dispersions of metal compounds in fuels.

Hitherto it has been possible to prepare oil dispersions of carbonates and hydroxides of metals such as alkaline earth metals. It has not however been possible to prepare colloidal dispersions of certain salts. In accordance with this invention new compositions comprise a fuel containing a colloidal dispersion of a sulphate, halide or phosphate of an alkaline earth metal, said metallic compound having an average particle size of less than 0.2-micron diameter. Such compositions may be used as hydrocarbon fuels containing an antismoking agent.

The preferred fuels are those which boil above 100 C., especially above 130 C. Fuels which are particularly suitable are liquidhydrocarbon fuel oils, especially petroleum distillate fuels boiling above 200 C., and including light fuel oils, gas oils used as fuel for diesel engines, heavy oils used in furnaces, kerosene, diesel fuels and residual fuels. Especially suitable fuels are diesel fuels, e.g., those containing cracked distillates, e.g., 15 to 30 percent by weight.

The preferred alkaline earth metals from which the compounds are derived are barium and strontium. Although any halide may be used it is preferable if the chloride is used. The particularly preferred compounds which form colloidal dispersions are barium chloride and barium sulphate, although magnesium chloride is a convenient compound to use.

The average particle size of the sulphate, halide or phosphate is less than 0.2 micron diameter and it is found that filtration of the fuel containing the colloidal dispersion through a 0.2 micron microfilter does not remove suspension of colloid. Centrifugation shows that often most of the particles have a particle size of less than 0.1 micron diameter, and hence the average particle size of such dispersions is less than 0.1-micron diameter.

The dispersion is preferably stabilized by the presence of a small proportion by weight of a surface active agent which is conveniently introduced during the method of preparation as hereinafter described. Examples of such surface active agents include phosphosulphurised hydrocarbons, amines, alkyl phenols, and bisphenols.

The specific method of making the colloidal dispersions of the invention varies according to whether one wishes to make the sulphate, halide or phosphate. In general however, one can prepare the required dispersions by reacting a dispersion of an alkaline earth metal oxide, hydroxide, carbonate, phenate, or salt of any other weak acid in an oil or fuel with the appropriate acid, or with the ammonium salt of the acid, or a salt formed from the acid and a volatile amine, e.g., methyl amine, or ethylamine. By volatile amine is meant an amine which distills off from the reaction mixture when said alkaline earth metal oxide, hydroxide, carbonate, phenate, or salt of weak acid is added to the reaction mixture.

Thus, to make a dispersion of an alkaline earth metal halide, the product obtained by reacting carbon dioxide with mixture of an alkaline earth metal base (for example barium oxide), an alkyl phenol and a phosphosulphurised hydrocarbon (e.g., phosphosulphurised polybutene) in the presence of a diluent oil or fuel is diluted with a diluent (e.g., heptane or a fuel) and reacted with a hydrogen halide (e.g., hydrogen chloride).

Alternatively, for example the carbonate, e.g., barium carbonate, dispersed in a mineral oil or fuel is reacted with the hydrogen halide. When hydrogen halide is used as a reactant it is preferable if the gas is bubbled into the reaction mixture for a few hours.

To make a dispersion of an alkaline earth metal sulphate, one can react the phenate of the alkaline earth metal prepared in situ with ammonium sulphate. Thus, a mixture of an amine (e.g., a mono N-long-chain fatty acid mono substituted diamine) and a phenol dissolved in a mineral oil or fuel is reacted with aqueous ammonium sulphate. An alkaline earth metal hydroxide (e.g., barium hydroxide pentahydrate) is then added. This is followed by alternate additions of aqueous ammonium sulphate and alkaline earth metal hydroxide until the required amounts of sulphate and alkaline earth metal ions have been added. Alternatively one can react a dispersion of the alkaline earth metal phenate in an oil or fuel with dilute sulphuric acid; or react a dispersion of the alkaline earth metal oxide, hydroxide, carbonate, or salt of a weak acid in an oil or fuel with ammonium sulphate or dilute sulphuric acid, or the salt of sulphuric acid and a volatile amine.

The preparation of the dispersion of the alkaline earth metal phosphate is similar in that a dispersion of an alkaline earth metal oxide, hydroxide, carbonate, phenate, or salt of a weak acid in an oil or fuel is reacted with ammonium phosphate or a phosphate of a volatile amine or preferably with orthophosphoric acid.

If the dispersion has been prepared in the presence of an oil the composition of this invention is obtained by adding the dispersion to a fuel. If, on the other hand, it has been prepared in the presence of a fuel it need not be added to a fuel unless dilution is required.

The amount of alkaline earth metal compound dispersed in the fuel can vary considerably according to requirements. It is also limited to some extent of course, by the nature of the alkaline earth metal compound and the fuel. When used as an antismoking additive the amount of alkaline earth metal compound dispersed in the fuel is preferably between 0.001 and 10.0 percent e.g., between 0.01 and 5 percent by weight of metal based on the weight of the fuel. For other applications e.g., as fuel concentrates the quantity of alkaline earth metal compound may be considerably higher, e.g., up to 50 percent by weight ofmetal based on the weight ofthe fuel.

Preparation 1 A dispersion of barium carbonate in a mineral oil was prepared by reacting carbon dioxide with a mixture of 37.5 parts of barium hydroxide pentahydrate, 2.8 parts of a phosphosulphurised polybutene of M.W. about 900, 5.6. parts ofa C -C alkyl phenol, and 43.4 parts ofa mineral lubricating oil at 260 F. Excess carbon dioxide was blown in during the reaction, which occupied 3 hours. The product was stripped in vacuo at 300 and filtered.

The resulting dispersion of barium carbonate, which had an average particle size of about 0.05-micron diameter, (34.4 percent) was mixed with an equal volume of heptane and saturated with dry hydrogen chloride for 2 hours. Carbon dioxide and hydrogen sulphide were evolved, and the required dispersion of barium chloride was obtained by stripping under vacuum. The stripped product contained 12.4 percent by weight of chlorine compared with a theoretical quantity of 12.2 percent by weight.

Preparation 11 A mixture of 12 g. of mono-N-tallow oil fatty acid substituted 1,3 propylene diamine, 12 g. of bisphenol (obtained from the reaction with C 40 alkyl phenols with formaldehyde) and 76 g. of a mineral lubricating oil having a viscosity at F. of 1 l3 S.S.U., and a viscosity at 210 F. of40 SSU with a viscosity index of 82, was stirred at C. 7.0 ml. of a solution prepared by making up 35 g. of ammonium sulphate to 70 ml. with water was added carefully. When the reaction ceased 7.0 g. of barium hydroxide pentahydrate was added carefully. 7.0 ml. of ammonium sulphate solution and 7.0 g. barium hydroxide were added alternately until the 35 g. of ammonium sulphate and 70 g. of barium hydroxide pentahydrate had been added. The mixture was stripped in vacuo and filtered. The product contained 2.15 percent barium and its specific gravity at 25 C. was 1.29. The residue on dialysis was proved to be barium sulphate by X-ray analysis. The average particle size of the dispersion in oil was about 0.05-micron diameter.

Preparation III A mixture of 25 g. of mono-Ntallow oil fatty acid substituted 1,3 propylene diamine, 25 g. of bisphenol (obtained from the reaction of a C-,C, alkyl phenol with formaldehyde) and 60 g. of mineral oil (as in Preparation II) was stirred at 130 C. and 10 g. of barium hydroxide pentahydrate was added. When the reaction subsided, there was added 5 ml. of a solution of 75 g. 98 percent sulphuric acid made up to 100 ml. with water. Alternate additions of g. of barium hydroxide pentahydrate and 5 ml. of the sulphuric acid were made, until 130 g. of the barium hydroxide and 65 ml. of the sulphuric acid solution had been added in all. Nitrogen was blown through the solution to remove all traces of water, and the product was filtered.

A dispersion containing 50.6 percent by weight of barium sulphate was obtained, and had an average particle size of about 0.05-micron diameter.

Preparation IV Preparation V The process described in Preparation III was repeated, using in this case 10 lB-gram lots of barium hydroxide penta hydrate and 10 S-milliliter lots of a solution of 36 g. 90 percent phosphoric acid made up to 50 ml. with water.

The product contained 27.5 percent dispersed barium phosphate, of average particle size of about 0.05-micron diameter.

EXAMPLE Blends containing 0.07 wt./vol% of barium which were made by dissolving the calculated amounts of the dispersions prepared in Preparations I, III and IV in autodiesel fuel were tested in a Petter AV-l diesel engine fitted with a I-Iartridge smoke meter on its exhaust. The average particle size of the barium compound was in each case about 0.05 micron. The smoke emission was measured at different engine power outputs with the following results:

I-lartridge Smoke Meter Reading Engine Fuel Fuel Fuel Bl-l P Untreated fuel BaC I 2 E2150 SrSO,

1.85 23 11 13 [0 3.70 35 I2 14 21 4.01 43 l7 I5 31 4,18 52 22 18 4] What is claimed is:

1. A process for producing a colloidal dispersion of an alkaline earth metal salt of an inorganic acid, said salt having an average particle size of less than 0.2 micron, said colloidal dispersion having the property of reducing the smoke-forming tendency of a liquid hydrocarbon fuel boiling above C. when incorporated therein, which comprises preparing a mixture of a long-chain fatty acid amine an alkyl phenol, and a hydrocarbon oil, said mixture containing from 2 to 25 parts by weight of said amine and from 12 to 25 parts by weight of said alkyl phenol for each 60 to 76 parts by weight of hydrocarbon oil, forming said salt by reacting in said mixture at an elevated temperature sufficient to drive off volatile reaction products, an alkaline earth metal reactant selected from the group consisting of an alkaline earth metal oxide, hydroxide, carbonate or alkyl phenate, with an acidic reactant selected from the class consisting of sulphuric acid, ammonium sulphate, and C 0 C amine sulphate, phosphoric acid, ammonium sulphate, 1 to C amine phosphate, said reaction being effected by stepwise addition of alternate portions of alkaline earth metal reactant and acidic reactant.

2. Process as defined by claim 1 wherein said alkyl phenol is an alkyl bisphenol obtained from reaction of C to C alkyl phenol with formaldehyde.

3. Process as defined by claim 1 wherein said amine is a mono-N long -chain fatty-acid-substituted diamine.

4. Process as defined by claim 1 wherein said alkaline earth metal salt comprises barium phosphate.

5. Process as defined by claim 1 wherein said alkaline earth metal salt comprises strontium sulphate.

6. Process as defined by claim 1 wherein said alkaline earth metal salt comprises strontium sulphate.

7. A process for producing a colloidal dispersion of an alkaline earth metal salt of an inorganic acid, said salt having an average particle size of less than 0.2 micron, said colloidal dispersion having the property of reducing the smoke-forming tendency of a liquid hydrocarbon fuel boiling above 130 C. when incorporated therein, which comprises preparing a mixture of a long chain fatty acid amine, an alkyl phenol, and a hydrocarbon oil, said mixture containing from 12 to 25 parts by weight of said amine and from 12 to 25 parts by weight of said alkyl phenol for each 60 to 76 parts by weight of hydrocarbon oil, reacting in said mixture at about 130 C. an alkaline earth metal reactant selected from the group consisting of an alkaline earth metal oxide, hydroxide, carbonate or alkyl phenate, with an acidic reactant selected from the class consisting of sulphuric acid, ammonium sulphate, C to C amine sulphate, phosphoric acid, ammonium phosphate, and C, to C amine phosphate, said reaction being effected by stepwise addition of alternate portions of alkaline earth metal reactant and acidic reactant, and removing volatile reaction products from said resultant dispersion, the amount of alkaline earth metal reactant being sufficient to incorporate into said dispersion up to 50 weight percent of said alkaline earth metal, based on the weight of the dispersion.

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2. Process as defined by claim 1 wherein said alkyl phenol is an alkyl bisphenol obtained from reaction of C7 to C10 alkyl phenol with formaldehyde.
 3. Process as defined by claim 1 wherein said amine is a mono-N long -chain fatty-acid-substituted diamine.
 4. Process as defined by claim 1 wherein said alkaline earth metal salt comprises barium phosphate.
 5. Process as defined by claim 1 wherein said alkaline earth metal salt comprises strontium sulphate.
 6. Process as defined by claim 1 wherein said alkaline earth metal salt comprises strontium sulphate.
 7. A process for producing a colloidal dispersion of an alkaline earth metal salt of an inorganic acid, said salt having an average particle size of less than 0.2 micron, said colloidal dispersion having the property of reducing the smoke-forming tendency of a liquid hydrocarbon fuel boiling above 130* C. when incorporated therein, which comprises preparing a mixture of a long chain fatty acid amine, an alkyl phenol, and a hydrocarbon oil, said mixture containing from 12 to 25 parts by weight of said amine and from 12 to 25 parts by weight of said alkyl phenol for each 60 to 76 parts by weight of hydrocarbon oil, reacting in said mixture At about 130* C. an alkaline earth metal reactant selected from the group consisting of an alkaline earth metal oxide, hydroxide, carbonate or alkyl phenate, with an acidic reactant selected from the class consisting of sulphuric acid, ammonium sulphate, C1 to C2 amine sulphate, phosphoric acid, ammonium phosphate, and C1 to C2 amine phosphate, said reaction being effected by stepwise addition of alternate portions of alkaline earth metal reactant and acidic reactant, and removing volatile reaction products from said resultant dispersion, the amount of alkaline earth metal reactant being sufficient to incorporate into said dispersion up to 50 weight percent of said alkaline earth metal, based on the weight of the dispersion. 